For the sauce:
3 tablespoons light soy sauce
1/2 teaspoon Chinese black vinegar (preferred), or rice wine vinegar
6 tablespoons homemade chili oil, plus 2 teaspoons of the toasted chili from the oil
Salt, to taste
1 teaspoon sesame paste or tahini
2 teaspoons sugar
2 cloves of garlic, finely minced
To garnish (optional):
Chopped scallion